In a large skillet, cook ground beef and diced onions over medium heat until beef is browned and onions are tender. Drain excess fat.

Add taco seasoning and tomato sauce to the skillet. Stir to combine and let simmer for 5 minutes.

In a 9×13-inch baking dish, layer half the corn chips to create a crunchy base.

Spread the beef mixture evenly over the chips.

Sprinkle shredded cheddar cheese on top of the meat layer.

Add remaining crushed chips over the cheese.

Bake at 350°F for 15-20 minutes, until the cheese is melted and bubbly.

Remove from oven and top with diced tomatoes, green onions, sour cream, and chopped cilantro before serving.